New Zealand is to join Australia's case in the International Court of Justice to end Japanese whaling in the Southern Ocean.

New Zealand has filed its intention to the Court, saying that it is a party to the whaling convention.

Australia is arguing that Japan's whaling program breaches the international ban on commercial whaling.

New Zealand Foreign Minister, Murray McCully, says his country has worked hard with Japan for more than three years to find a diplomatic solution to the whaling issue, and he's disappointed that these efforts have failed.

He says the New Zealand government will continue to use all avenues possible to try to stop Japanese whaling in Antarctic waters.

Professor of International Law at the Australian National University, Donald Rothwell, says New Zealand's move is not surprising.

"The New Zealand argument will frame around an interpretation of Article 8 which is very much based on an anti-whaling position," he said.

"This is consistent with a very long-standing position that New Zealand has taken in the International Whaling Commission and which successive New Zealand governments have put in the public domain for the last 20 years."

Professor Rothwell says New Zealand's move may pave the way for other countries to join the action.

"New Zealand has argued before the Court that because it is a state party to the whaling convention then, consistent with the Court statute, it is able to make such a submission," he said.

"So it will be interesting to see whether other countries who are pro-conservation - or indeed pro-whaling - also follow New Zealand's precedent."